Lab midterm Bio40B Flashcards
Components of a reflex arc:
- Receptor
- Sensory Neuron
- Integration center
- Motor Neuron
- Effector
AKA…..R.S.I.M.E
Somatic spinal reflexes:
- Stretch reflexes
- Crossed extensor reflexes
- Superficial cord reflexes
- Cranial nerve reflexes
Longitudinal Fissure:
Divides the cerebral hemisphere into right and left
Transverse Fissure
Divides cerebrum from the cerebellum
Central Sulcus
Divides the frontal lobe from the parietal lobe
Lateral Sulcus
Separates the temporal lobe from the frontal and part of the parietal lobe
Parieto-occipital sulcus
divides the parietal lobe from the occipital lobe
Protections of the spinal cord:
- Vertebrae
- Meninges: Dura mater; arachnoid mater; Pia mater
- Cerebrospinal Fluid
Two grooves run the length of the SC
- Posterior median sulcus
- Anterior median fissure
White matter(SC)
- Composed of myelinated and unmyelinated axons
- Allows communication between SC and brain
- Classified by type: ascending fibers: descending fibers; commissural fibers
Gray matter(SC): shaped like the letter H
- Dorsal horns: consist of interneurons
- Ventral and Lateral horns: contain cell bodies of motor neurons
- Gray commissure: contains central canal
Ventral roots
arise from the anterior horn and contain motor fibers(efferent)
Dorsal roots
arise from sensory neurons in the dorsal root ganglion and contain sensory fibers(afferent)
Cervical plexus: C1-C5
includes phrenic nerve
Brachial plexus: C5-T1
includes axillary nerve, Ulnar nerve, median nerve, radial nerve
Lumbar plexus: L1-L4
femoral nerve
Sacral plexus: L4-S4
Sciatic nerve
Pupillary light reflex:
Tests for optic nerve II and III
Eye layers
- Fibrous layer
- Vascular layer
- Sensory layer; Retina
Fibrous layer(eye)
Sclera and Cornea
Vascular layer(eye)
Choroid, Ciliary body and Iris
Sensory layer; Retina
Pigmented layer; Neural layer
Ciliary muscle(eye)
changes lens thickness to allow light to be properly focused on the retina
Vitreous humor in posterior segment(eye)
Jellylike, transmits light< maintain shape of eyeball and holds the retina in place
Aqueous humor in Anterior segment(eye)
filled with liquid, replaced continuously, brings nutrients
Sensory layer(Retina) contains photoreceptors:
- Rods
- Cones
- Signals leave the retina toward the brain through the optic nerve
What is the sclera?
White outer layer of eyeball. At the front of eye it is continuous with the cornea
What is the cornea and what does it do?
Acts as outermost lens. The aperture
What is the function of the Optic nerve?
Transfer visual information from retina to vision centers in brain via electrical impulses
What does the Iris do?
responsible for controlling diameter and size of pupil and thus amount of light reaching retina. Eye color is defined by that of Iris
What is the Pupil?
Light enters the eye through the pupil
What is the function of the Ciliary muscle?
fibers that suspend the lens in position during accommodation, enabling changes in lens shape for light focusing
What does the Lens do?
Helps to focus light and images on your retina
What is the Vitreous humor?
transparent jellylike tissue filling the eyeball behind the lens
Where is the blind spot located?
where the optic disc is located(aka the optic nerve head).
What is the Retina?
Layer at back of eyeball containing cells that are sensitive to light and that trigger nerve impulses that pass via the optic nerve
What is the function of the Tapetum?
retroreflector. reflex visible light back through the retina.
Do humans have a Tapetum layer?
Humans do not have a Tapetum layer
Which structure is made up of circular and radial smooth muscles?
Ciliary body
The lens divides the eye into:
Anterior and Posterior chambers
Choose the correct answer
A. Cataract is when the lens becomes more opaque.
B. Cataract is when the aqueous humor does not drain well
A
Where is the origin of the Optic nerve?
Retina
Lamellar or Pacinian corpuscles
responsible for sensitivity to vibrations and pressure
Rods and cones. Highest concentration of these are located in:
The Macula
The suspensory ligaments and ciliary muscle control the shape of the following structure:
Lens
Monosynaptic reflexes:
Sensory neuron synapse directly on a motor neuron(no interneuron).
Polysynaptic reflexes:
at least one interneuron between the sensory and motor neuron
Ipsilateral reflexes:
A reflex response that effects the same side as the stimulus
Contralateral reflexes:
A reflex that affects the opposite side of the body from the stimulus
Consensual reflex:
Occurs on both sided of the body at the same time.
Intersegmental reflex:
The integration occurs at different levels in the spinal cord.
